Gaseous electric discharge device



Dec. 18, 1934. P|RAN| 1,984,428

GASEOUS ELECTRIC DISCHARGE DEVICE Filed Dec. 21, 1932 m 9 Wm m 6 I I .a

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IINVENTOR Y ATTORNEY Patented Dec. 18, 1934 GASEOUS ELECTRIC DISCHARGE DEVICE Marcello Pirani, Berlin-Wilmersdorf, Germany,

assignor to General Electric Company, a cor- Duration of New York Application December 21, 1932, Serial No. 648,304

In Germany December 24, 1931 v 3 Claims.

The present invention relates to gaseous electric discharge devices generally .and more particularly the invention relates to methods and means for starting such devices into operation.

It is now known in the art that the starting of gaseous electric discharge devices is facilitated by an electrically conducting member'extending along the discharge path and electrically conthe container of the device. Where the container is at a temperature of approximately 100 C. or more during the operation of the device, as is frequently the case in high intensity electric lamp devices, particularly those containing a metal vapor, such as sodium or magnesium, the thin, electrically conducting member on said container is frequently burned through which renders it ineffective for starting purposes. Further, where the electrically conducting member is a metal strip attached to the glass container the diiference in the 'coemcients of expansion of the metal strip and the glass container results in physical strain on the metal strip which either loosens it on the container or causes a break therein, either of which reduces or destroys its usefulness in starting the electric discharge device.

The object of the present invention is to provide an electric discharge device having an electrically conducting member on the walls of the container thereof to facilitate the starting of the electric discharge therein in which the above mentioned diflieulties are entirely avoided. A further object of the invention is to provide a conducting memberwhich is easily attached to the container of an electric discharge device. Still further objects and advantages attaching to the device'and to its use and operation will be apparent to those skilled in the art from the following particular description and from the appended claims.

The invention attains its object by using a wide mesh net of thin metal wires as theelectrically conducting member. Said net is made to conform in shape to that of the container of the electric discharge device, but due to the wide mesh thereof and the thinness of the wires said net offers little obstruction to the light emitted by the luminous electric discharge in the device. The danger of rupturing the metal net by physical strains due to the disparity in expansion between the metal of said net and said glass container is reduced to a minimum by the flexibility of said net. As the heat radiating surface of the metal wire net is large in comparison to its bulk the danger of a rupture thereof by heat is reduced to a minimum. Even though the net should be broken in one or more places there would still remain a number of electrically conducting wires in any cross section of the deviceso that the electric discharge in the device is quickly and positively started into operation throughout the life of the device.

In the drawing accompanying and forming part. of this specification two embodiments of the invention are shown in a side elevational view.

Referring to the drawing (Fig. 1 )the new and novel gaseous electric discharge device comprises a tubular container 1 having stems 2 and 3 one at each end thereof. Electrode leads 4 and 5 are sealed into the stems 2 and 3 respectively. Electrodes 6 and 7 are mounted on said leads 4 and 5 respectively. Said electrodes 6 and '7 are of the sintered, mixed metal and oxide type known in the art as Pirani electrodes and are electron emitting when heated. Said container 1 has a gaseous atmosphere therein comprising a rare gas, such as neon, or a metal vapor, such as mercury, or a mixture of gas and metal vapor,

such as neon and sodium vapor. A metal wire net 8 of wide mesh and tubular shape is stretched tightly over the external wall of said container 1. Said net 8 extends the length of said container 1 between said electrodes 6 and '1 and overlaps said electrodes 6 and 7. Said net 8 is applied to said container 1 by slipping said net 8 over one end of said container 1 which simplifies the manufacture of the electric discharge lamp device and said net 8 is maintained in position on said container 1 by the friction resulting from the tight fit between these two members of the device.

Said net 8 is electrically connected to the lead-'4 of said electrode 6 and when current is. applied across the terminals of the device an auxiliary electric discharge takes place between said net 8 and said electrode '7. This auxiliary discharge extends along the discharge path between said electrodes 6 and 7 and heavily ionizes said discharge path to facilitate the starting of the main discharge between said electrodes 8 and 7.

It will, of course, be understood that, as shown in Fig. 2, said net 8 is connected to both of said electrode leads 4 and 5, where desired, and that an electrical resistance 10 is connected into the lead 9 where the electrical resistance of net '8 is,

not sufllcient. Said net 8 is made up of electri-, cally separate sections and said sections are coni nected to each other through a resistance 11, where desired.

What I claim as new and desire to secure by Letters Patent of the United States is:- r

1. An electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, a flexible wide mesh net of thin wires having large heat radiating surface and small bulk of conducting material applied to the wall 0! said container and extending along that part of said container between said electrodes, said net being connected to at least one of said electrodes.

2. An electric discharge device comprising a.

container, electrodes sealed therein, a gaseous atmosphere therein, a flexible wide mesh net of thin wires having large heat radiating surface and small bulk of conducting material applied to the wall of said container and extending along that part of said container between said electrodes, said net being connected to at least one of said electrodes and overlappin both of said electrodes.

3. An electric discharge device comprising a container, electrodes sealed therein. a gaseous atmosphere therein, a wide mesh net of thin wires of conducting material applied to the wall or said container and extending along that part of said container between said electrodes, said net being connected to both of said electrodes through a resistance and being in sections connected to each other through a resistance.

mm "'ELLO PIRANI. 

